SIGNL4

SIGNL4 is a mobile alerting and on-call duty management service that transforms emails, webhooks, and IoT events into reliable push, SMS, and voice alerts with acknowledgement tracking, escalation, and team on-call scheduling. The platform provides both an inbound webhook for sending alerts and a REST API for managing alerts, statuses, annotations, and team data. Authentication uses a team or webhook secret embedded in the URL path or supplied via the X-S4-Api-Key header.

SIGNL4 publishes 2 APIs on the APIs.io network: Events API and Webhook API. Tagged areas include Alerting, Incident Management, On-Call, Mobile Alerts, and Notifications.

SIGNL4’s developer surface includes authentication, documentation, pricing, signup flow, support, engineering blog, GitHub presence, and 5 more developer resources.

🌐 Visit website 📡 Source on GitHub

33.0/100 thin ▬ flat Agent 28/100 agent aware Full breakdown ↓
scored 2026-08-05 · rubric v0.9.1

AccessSelf serve

4 APIs

AlertingIncident ManagementOn-CallMobile AlertsNotificationsDevOpsIT OperationsMonitoring

Kin Score

Kin Score How this is scored →
scored 2026-08-05 · rubric v0.9.1

Composite quality — 33.0/100 · thin

Contract Quality 16.0 / 25

Developer Ergonomics 5.2 / 20

Commercial Clarity 3.7 / 20

Operational Transparency 0.7 / 13

Governance 0.0 / 12

Discoverability 7.4 / 10

Agent readiness — 28/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/signl4: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 4

Individual APIs this provider publishes, each with its own machine-readable definition.

Get Started 1

Portal, sign-up, and the first successful call

Signup

Signup

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHub

GitHub

Access & Security 3

Authentication, authorization, and security posture

TrustCenter

TrustCenter

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 1

Pricing, plans, and the legal terms of use

Pricing

Pricing

Company 3

The organization behind the API

LinkedIn

Website

Website

Blog

Blog

Source (apis.yml)

aid: signl4
name: SIGNL4
description: SIGNL4 is a mobile alerting and on-call duty management service that transforms emails, webhooks, and IoT events
  into reliable push, SMS, and voice alerts with acknowledgement tracking, escalation, and team on-call scheduling. The platform
  provides both an inbound webhook for sending alerts and a REST API for managing alerts, statuses, annotations, and team
  data. Authentication uses a team or webhook secret embedded in the URL path or supplied via the X-S4-Api-Key header.
type: Index
accessModel:
  pricing: unknown
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Self-serve signup
  confidence: medium
  source:
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/signl4.png
tags:
- Alerting
- Incident Management
- On-Call
- Mobile Alerts
- Notifications
- DevOps
- IT Operations
- Monitoring
url: https://raw.githubusercontent.com/api-evangelist/signl4/refs/heads/main/apis.yml
created: '2026-05-11'
modified: '2026-05-11'
specificationVersion: '0.19'
apis:
- aid: signl4:inbound-webhook
  name: SIGNL4 Inbound Webhook API
  description: Simple HTTPS webhook endpoint for triggering mobile alerts in SIGNL4 from any monitoring, ITSM, or IoT tool.
    Accepts JSON payloads with Title and Message fields plus optional X-S4 control parameters for service categorization,
    location, alerting scenario, and external identifiers. Authentication uses a unique team or webhook secret embedded in
    the URL path.
  humanURL: https://docs.signl4.com/integrations/webhook/webhook.html
  baseURL: https://connect.signl4.com/webhook
  tags:
  - Webhook
  - Inbound
  - Alerting
  - Mobile Push
  properties:
  - type: Documentation
    url: https://docs.signl4.com/integrations/webhook/webhook.html
  - type: APIReference
    url: https://connect.signl4.com/webhook/docs/index.html
  - type: Code Samples
    url: https://github.com/signl4/code-snippets
- aid: signl4:rest-api
  name: SIGNL4 REST API
  description: RESTful API for programmatic alert lifecycle management including creating events, acknowledging or closing
    alerts, annotating alerts, and retrieving team data. Authentication is via X-S4-Api-Key header with the team or webhook
    secret.
  humanURL: https://docs.signl4.com/integrations/rest-api/rest-api.html
  baseURL: https://connect.signl4.com/api
  tags:
  - REST
  - Alert Management
  - Events
  - Incident Response
  properties:
  - type: Documentation
    url: https://docs.signl4.com/integrations/rest-api/rest-api.html
  - type: Overview
    url: https://www.signl4.com/webhook-rest-smtp-api-integration/
  - type: Code Samples
    url: https://docs.signl4.com/samples/code-samples/code-samples.html
- aid: signl4:signl4-events-api
  name: SIGNL4 Events API
  description: The Events API from SIGNL4 — 1 operation(s) for events.
  humanURL: https://docs.signl4.com/integrations/webhook/webhook.html
  baseURL: https://connect.signl4.com/webhook
  tags:
  - Events
  properties:
  - type: OpenAPI
    url: openapi/signl4-events-api-openapi.yml
- aid: signl4:signl4-webhook-api
  name: SIGNL4 Webhook API
  description: The Webhook API from SIGNL4 — 1 operation(s) for webhook.
  humanURL: https://docs.signl4.com/integrations/webhook/webhook.html
  baseURL: https://connect.signl4.com/webhook
  tags:
  - Webhook
  properties:
  - type: OpenAPI
    url: openapi/signl4-webhook-api-openapi.yml
common:
- type: AgenticAccess
  url: agentic-access/signl4-agentic-access.yml
- type: TrustCenter
  url: security/signl4-trust-center.yml
- type: DomainSecurity
  url: security/signl4-domain-security.yml
- type: Authentication
  url: authentication/signl4-authentication.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/signl4
- type: Website
  url: https://www.signl4.com
- type: Documentation
  url: https://docs.signl4.com
- type: Pricing
  url: https://www.signl4.com/pricing/
- type: Signup
  url: https://account.signl4.com/register
- type: Support
  url: https://support.signl4.com
- type: Blog
  url: https://www.signl4.com/blog/
- type: GitHub
  url: https://github.com/signl4
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

SIGNL4

Kin Score

APIs 4

SIGNL4 Inbound Webhook API

SIGNL4 REST API

SIGNL4 Events API

SIGNL4 Webhook API

Open Collections 1

SIGNL4 Webhook and REST API

Security Posture 3

Signl4 Authentication

Signl4 Domain Security

Signl4 Trust Center

Agentic Access 1

Signl4 Agentic Access

Resources